Rpms change when you press the brake hard

[Johngreg]

hi there, my 04 cobra gets a issue which almost feels like a vacuum leak. When I stop at a light and press the brake the rpms will drop and rise like a vacuum leak. Any tip for this? I’ve tried cleaning the MAF, IAT. nothing so far.

 

[MG0h3]

Does this occur as you are coming to a stop, or when you are already stopped?

I know there was an issue with the factory tune that would cause a stall.

My car tends to hang at like 1000 dropping to 750 right as I make a stop.


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[3xBlackCobra]

My rpm's would dip and almost stall at times when stopping hard after a good pull. I cleaned the iac with carb cleaner and it's been better since

 

[01yellercobra]

It's probably the load change on the power steering pump. The brakes use the pump for pressure assist. If you push the brake it changes the load and probably takes the engine a second to catch up.

 

[Johngreg]

Does this occur as you are coming to a stop, or when you are already stopped?

I know there was an issue with the factory tune that would cause a stall.

My car tends to hang at like 1000 dropping to 750 right as I make a stop.


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Once I’m at a steady stop

 

[52merc]

Pushing the brake down, even at a stop, places a load on the power-steering pump. The harder you press, the more the load. It is relative to the pressure you are trying to apply, not the speed of the rotors. When you are driving along and press the brakes, you will likely not feel anything as the increased load is relatively small compared to the load of moving down the road. Stopped, at idle, there are relatively small loads, so you may feel the additional load and a short decrease in idle speed until the IAC can correct it. It is possible that your IAC may be getting weak, making it respond a little slower.

 

[03 Cobra DSG]

If you replace the IAC make sure you buy a ford one, don’t buy one from the local pets stores.


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[Zemedici]

If you replace the IAC make sure you buy a ford one, don’t buy one from the local pets stores.


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preach. OEM only.

 

[Goose17]

If you replace the IAC make sure you buy a ford one, don’t buy one from the local pets stores.


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Did something bite you from the local pets store?

 

[03 Cobra DSG]

Lol what you guys don’t buy your iac’s from petsmart?


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